Children waiting for new hearts live longer on pump

Gene Emery

NEW YORK (Reuters Health) - Hooking seriously-ill children to a pump that assists the heart helps them live longer than those hooked to a heart-lung machine while they await a heart transplant, doctors report in a new study.

"The device did well; more than 80% made it to transplant," Dr. Daphne Hsu, chief of pediatric cardiology at the Children's Hospital at Montefiore Medical Center in New York, told Reuters Health. Hsu was not an author of the New England Journal of Medicine study, but was on the committee that looked at strokes and other serious side effects of the therapy.

A heart transplant can cure childhood heart failure - which occurs when the heart can't pump enough blood to the rest of the body - but the waiting list for children can be long. When children are put on conventional extracorporeal membrane oxygenation (ECMO) to keep them alive, only about 40 percent to 60 percent survive long enough to get a new heart.

Among the 24 smallest children, more than half whose hearts were helped by the pump, known as a ventricular assist device, were alive at the 174-day mark. By comparison, the median survival time was 13 days among a similar group of children who, in the past, had been kept alive with ECMO.

For larger children, ranging in weight from 4 kilograms (about 10 pounds) to 59 kg (about 130 pounds), median survival was 144 days with a pump from Berlin Heart, which funded the study along with the U.S. Food and Drug Administration.

Among similar children treated with ECMO, the average survival was just 10 days.

However, most of the children treated with the assist device developed serious side effects such as infection, stroke and bleeding.

Heart failure affects about five million people in the U.S. Most of them are adults, but about half of children with the condition die or have a transplant within five years, according to the authors of the study.

RESULTS NOT SURPRISING

To see if a ventricular assist device would prolong their lives, 17 centers in the U.S. and Canada used the Excor Pediatric device made by Berlin in children ranging from newborns to 15 years of age. Including costs of procedures and hospitalization, such devices typically cost in the tens or even hundreds of thousands of dollars, as does ECMO.

All had severe heart failure despite conventional care and were on a waiting list for a transplant. The surgery typically took about 3 hours.

It's not surprising that the pump would work better than ECMO, said Hsu, because ECMO "was made to be an artificial lung, actually. Children with lung problems usually need that kind of support for a few weeks and you can take them off. They recover."

But months can pass before a heart becomes available for transplant. ECMO equipment is not made to be used for that long.

"We've been trying to push the limits of ECMO because we had nothing else," said Hsu. "With the Berlin device, we can offer better long-term survival."

"Overall, 88% of the participants in cohort 1 (the smaller children) and 92% of those in cohort 2 (the larger children) survived to undergo either heart transplantation or weaning from the device," said the team, led by Dr. Charles Fraser of Texas Children's Hospital.

In both groups combined, 45.8 percent had major bleeding, 56.3 percent had infection and 29.2 percent had strokes.

Thanks to the new study, said Hsu, if a center uses the pump, "we have a better idea of how to take care of the patients, what the issues are and what we should worry about. So it's very valuable because it's the kind of data that's so rare to get."